Rendertarget attachments, texture and image changes (#358)

* Add multiple color outputs for fragment shaders

* Add registers and gal enums

* Use textures for framebuffers and split color and zeta framebuffers

* Abstract texture and framebuffer targets as an image

* Share images between framebuffers and textures

* Unstub formats

* Add some formats

* Disable multiple attachments

* Cache framebuffer attachments

* Handle format types

* Add some rendertarget formats

* Code cleanup

* Fixup half float types

* Address feedback

* Disable multiple attachments in shaders

* Add A4B4G4R4 image format

* Add reversed section for image enums

Ryujinx.Graphics/Gal/IGalFrameBuffer.cs

@@ -4,9 +4,13 @@ namespace Ryujinx.Graphics.Gal
 {
     public interface IGalFrameBuffer
     {
-        void Create(long Key, int Width, int Height);
+        void BindColor(long Key, int Attachment);
 
-        void Bind(long Key);
+        void UnbindColor(int Attachment);
+
+        void BindZeta(long Key);
+
+        void UnbindZeta();
 
         void BindTexture(long Key, int Index);
 
@@ -40,7 +44,6 @@ namespace Ryujinx.Graphics.Gal
             long             Key,
             int              Width,
             int              Height,
-            GalTextureFormat Format,
             byte[]           Buffer);
     }
 }